Cleaning pipe



July 20, 1937. G, MALMROS 2,087,694

CLEANING PIPE Filed Nov. 5, 1954 2 Sheets-Sheet l July 20, 1937. G. MALMRos 2,087,694

- CLEANING PIPE Filed Nov. 5, 1934 2 Sheets-Sheet 2 Dune-.anon oF emmen. P1 ow DmEc-rloN oF v cARRlER. FLow Patented July 20, 1937 TES PAEN FFICE CLEANING rien Gustaf Malmros,

Stockholm, Sweden 3 Claims.

The present invention relates to a method of cleaning pipes intended for the conduction of water, pulp, milk, beer, yeast-suspensions, wort, waste liquids such as drainage, etc. and in which after continued use troublesome deposits appear impeding the ow of the liquids.

Pipes of this type in general use in buildings are usually made of galvanized iron. After these pipes have been in use for some time incrustments appear therein, which arise partly from salts in the water, and partly from corrosion of the pipes. The greatest diculty, however, is caused by the thick and tough deposits of micro-organisms such as algae, bacteria, etc., which steadily increase.

The pipe cleaning method of the invention consists essentially in forcing a nely divided grinding or abrasive agent, such as sand, quartzor slag-powder, through a congested pipe by means of a gaseous carrier, such as air, under -2n pressure or vacuum, so that the main portions of the deposits on the inside of the pipe are successively ground 01T by the grinding agent and carried away by the ow of the carrier medium.

The invention will now be described in detail 25 with reference to the accompanying drawings, in

which:-

Figure 1 represents a longitudinal section through a pipe almost clogged by deposits on the inner wall thereof.

Figure 2 represents a cross section taken on the line 2-2 in Figure 1.

Figures 3-5 are cross sections, also on line 2 2.

in Figure 1, showing the same pipe after a continued treatment according to the invention.

Figures 6 and 7 illustrate schematically an arrangement of apparatus for carrying the method of the invention into eiect.

Figures 8 and 9 are longitudinal sections through a portion of a pipe illustrating how the 40 narrowest part of the channel may be cleared by reversing the direction of ow of the carrier medium and grinding or abrasive agent.

Figure 10 is a similar view illustrating the removal by a ilexible wire of a clot which prevents 45 passage of the carrier medium through the pipe. In Figure 1, the pipe I is made, for instance, of iron and has a zinc coating 2 on the inside wall thereof. For the purpose of describing the invention, it is assumed that the pipe is adapted for 50 the conduction of water to various outlets in a building. On this coating 2 a hard and fast layer 3 of salts and rust, etc. has been deposited. In this layer there are also embedded some old colonies of micro-organisms, which, however, 55 under the conditions existing at the time intended to be illustrated by the gure, may be regarded as dead and inactive. Inside of the layer 3 a powerful layer 4 of algae, bacteria, etc. has been formed which, after ten or twenty years of usage of the pipe, might reach such a thickness that the flow of water therethrough is very seriously impeded. In the figure a very narrow channel 5 is thus shown, varying in diameter to a few millimeters or possibly less. This channel is the only way through which the Water is still able to pass, and forms a Winding passage inside of the deposits. In practice, the cross sectional `area of this passage becomes so small that the amount of running water at a certain pressure is reduced to a fraction, perhaps down to a tenth, of the water normally running through the pipe. Such a pipe can be cleaned according to the present invention in a novel and ecient manner, that will be described with reference to Figure 6 in which is disclosed a main water supply line 6 in a building from which run a number of branches 1-I0. The branches are connected to various plumbing iixtures as shown in the drawings. At these different fixtures faucet valves are located for controlling the water ow. In cleaning the pipes of such a system, the main valve of the building is first closed and the water in the pipe system is drawn oi. The diierent faucet valves are next taken oi and each replaced by a coupling, of which the one half II, Figure 7, is screwed on the pipe while the other half I2 is plugged and put on to the first half. A compressor I 5 is then connected with a sand-injector I'I of known construction through a hose I6, the sand-injector I'I being preferably lled with sharp cornered sand. The sand-injector is in turn connected by a detachable hose coupling I3, yI4 to a hose I8. The other end of this hose is connected by a detachable hose coupling I9, 20 to a branch of the main line 6 in the top apartment of the house. Similarly in the cellar of the house a hose coupling 2 I, 22 is inserted in a suitable place in the main line, which coupling is connected by means of aflexible hose 23 and a detachable hose coupling 24, 25 to a device for reclaiming sand. This latter device may, for instance, consist of a container 21, in the upper part of which is an air outlet 28. 'I'he lower part of the outlet is surrounded by a protecting bag 29 orrthe like in order to prevent the spreading of expelled dust around the apparatus.

Inasmuch as the deposits oder a better surface to attack and loosen more easily from the walls of the pipe when they are comparatively dry than when they are moist, the pipe system to be cleaned may be dried before the sandblasting operation in any suitable manner, as by blowing hot air therethrough. This preliminary drying step may, however, be dispensed with since, as later pointed out. the dry sand which is carried into the pipe and caught by the moist, slimy deposits absorbs moisture therefrom and when subsequently removed by'reversal of. the air current carries the absorbed moisture with it. thereby drying the deposits.

When the sand-injector I1 and the'compressor I5 are coupled into the system and the compressor is started. The sand-carrying air current then passes through the hose I8, the main line 6 and the hose 23, back to the reclaiming device 21. The particles of sand are, in` this way, forced with great speed to strike, to grind and to carry away the slimy deposits, so that the free space or effective diameter of the channel opening in the pipe is successively increased until the deposits are all or nearly all removed and the walls of the channel become substantially smooth and parallel with the pipe walls.

In case the pipe line is -so plugged up that the grinding agent cannot get through the pipe but is caught Aby the slimy and gelatinous deposits 35, Figure 8, inside of the pipe, the method as above described can hardly be carried out. It is one of the objects of the invention, however, to make the cleaning possible in such cases also. Accordingly, after the water is drained olf, one end 36 of the pipe line is s'et under pressure and it is ascertained whether the air can easily escape at the other end 31. If then only a weak air current escapes, the above mentioned method may be modified in the following manner. After the finely divided grinding agent has been taken into the pipe by means of the carrier and caught, as at 38, by the deposits and thus prevented from passing through the pipe, the connections and direction of flow of the carrier under pressure are reversed, as indicated by Figure 9. The carrier then forces additional grinding agent 40 into the pipe in the opposite direction from the other end 31 of the pipe and carries away the earlier caught grinding agent 38. This operation is continued until either the current is again impeded or alternatively free passage of the grinding agent is obtained, in which former case the direction of application of the pressure of the carrier is again reversed and so on, and this step repeated, until free passage is obtained.

The operation can be explained as follows. Because of the small opening, perhaps a few millimeters, at the narrowest place 39, the speed of the carrier at the wider places is reduced and the grinding agent cannot be carried away through the pipe but is caught and held by the slimy and gelatinous deposits between the entrance of the pipe and the narrowest place 39. Hereby the grinding agent 38, for instance the sand, absorbs some moisture from the deposits.

Consequently, no sand can get through to the,

opposite end 31 of the pipe.` When the carrier is forced in from the opposite end 31 of the pipe, dry sand 40 will be caught by the deposits on the opposite side of the narrowest place 38, while the earlier caught sand 38 as well as also moisture absorbed thereon will be carried away by the air current. In this manner a successive drying of the deposits is produced, while at the same time the sand has a grinding effect on the deposits, until the narrowest parts, such vas 38, of the pipe are widened sumciently that the sand current can pass through the pipe line from one end to the sand blast in this part.

the other. As soon as this is accomplished, the Sandblasting is continued in the same direction until the deposits have been completely orsubstantially ground into pieces by the sand and, with the sand, carried away by the air current.

Under especially difficult conditions, as when a clot 4I, Figure 10, is formed or the like, it may sometimes happen that in spite of repeated reversals of the air pressure, free passage of the.

grinding or abrasive agent cannot be obtained. In such a case it may be convenient to proceed in the following manner: The coupling member 22, of the above described `arrangement in Figure 6, is removed, and a flexible steel wire 42, for instance piano wire, a steel spring or the like, which, preferably, is provided' at one end with an enlargement, loop or the likel 43, is fed into the main line 6 with a twisting movement, while at the same time air pressure is applied to the hose I 8. When the wire is forced in, part of the slime at 4I is torn away from the walls of the pipe whereupon, due to the action of the air pressure, a greater quantity of shine is generally freed at a certain moment and is quickly forced out of the line at the coupling 2I. In order to avoid spouting out of the refuse, it is convenient to surround the free end of the pipe with a protective covering, such as cotton waste or the like, in order to collect the slime. If necessary, the procedure may be repeated until the pipe is cleared sufficiently to permit free passage of the grinding or abrasive agent therethrough.

After the clot has disappeared, the Sandblasting can conveniently be continued in the manner previously described.

In cleaning one half inch to one inch pipes a pressure of six atmospheres is used, by way of example. This pressure might conveniently be increased in proportion to the diameter of the pipe. The particles of sand, rushing forward, tend to straighten the winding passage 5 and slowly to produce an opening according to Figures 3 to 5. In this way the effective or free diameter of the pipe, in practically all cases, is increased many times, and the water line is completely or nearly restored to its original capacity. If desired, the cleaning operation may be discontinued before the deposits are entirely removed so that the remaining layer may serve as a protection for the underlying pipe material.

It is evident that, because in practice the main line 6 is usually widest at the lower end and narrowest at the upper end, the upper part is cleaned most quickly, due to the greater speed of That this last mentioned part is clean is most easily noticed when the manometer of the compressor at full speed has dropped to a certain level that is regarded as suitable, for instance as a practical test from six to three and one half atmospheres. 'I'hen the compressor is shut oil' and the plugged coupling member I2 on one of the branches of the main pipe 6 for instance branch 1, is removed and replaced by the hose coupling I9. The plugged coupling member thus removed is instead connected with the coupling 20. As an alternative, the hose I8 can be arranged With T-pipe connections 3| to 34, so that one such T-pipe connection will be opposite each apartment ofthe building. Every T-pipe connection is provided with a coupling according to Figure 7. An extra hose is then connected between the end of one of the branch pipes, for instance 1, and the coupling of the corresponding T-pipe connection, for example 3I.

The Asand current is then forced through the branch pipe 1 and the latter is cleaned in the same way as described above in connection with the cleaning of the branch pipe of the main line 6 in the top apartment. Then the rest of the branch pipes on the same iloor are blasted.

In this manner the process is continued, apartment after apartment, until the whole pipe system is blasted clean. It is not necessary to clean the different apartments in the above mentioned order, since any other convenient order may be followed.

The method according to the invention may also be used to advantage with a combination of pipe lines of different diameters.

In practice there has not been any difficulty in blasting angular pipes, and indeed the method can be performed with pipe systems of almost any number of elbows coupled in series.

In regard to the quality of the sand that should be used, it might be of advantage at the beginning of the blasting to use a relatively ne sand, and later to continue with coarser sand.

As it is known that an air current of sand which is forced through pipe lines of elastic Walls, for instance, rubber hose, does not wear the interior surface thereof to any appreciable degree, it is surprising that it is possible to tear away the slimy and gelatinous deposits inside of Water pipes by the method of the present invention. A possible explanation is that the pipe lines now under, consideration are themselves rigid and iixedly mounted in the building so that they can not vibrate.

Instead of air as the carrier of the grinding agent other gases, such as chimney gases, might be used. In place of sand as the abrasive or grinding agent other finely divided materials, such as quartzand slag-powder, might be used.

Various other changes, which will now suggest themselves to those skilled in the art, may be made in the details of the procedure and the means employed for carrying out the disclosed method without departing from the spirit of the invention. Reference is therefore to be had to the appended claims for a denition of the limits of the invention.

What is claimed is:

1. A method for removing such deposits of salts and algae in water pipe lines as leave only a narrow channel allowing a restricted flow of water through such pipes, comprising the steps of blowing a gas current laden with an'abrasive material of a relatively small grain-size through the channel until the cross sectional area thereof is increased to a desired size, and thereafter blowing a'gas current laden with an abrasive material of a relatively coarser grain-size through the widened channel to complete the abrasion.

2. A method for removing such heavy moist deposits of salts and algae in water pipe lines as leave only a narrow channel considerably impeding the iiow of water therethrough, comprising the steps of draining oi the water from the pipe line to be cleaned, forcing a gas current laden with dry comminuted abrasive material into the pipe line in a certain direction until a substantial portion of the material has adhered to the moist deposits and substantially prevents the further passage of the gas current through the pipe line, and then forcing a 'gas current laden with fresh dry comminuted abrasive material through the pipe line in the reverse direction until the adherent material and its absorbed moisture have been removed, thereby drying the deposits, and a substantial part of the deposits has been abraded'.

3. A method for removing such heavy moist deposits of salts and algae in water pipelines as leave only a narrow channel considerably impedng the ow of water therethrough, comprising the steps of draining oil:` the water from the pipe line to be cleaned, forcing a gas current laden with dry comminuted abrasive material into thepipe line in a certain direction until a substantial portion of the material has adhered to the moist deposits and substantially prevents the further passage of the gas current through the pipe line, forcing a gas current laden with fresh dry comminuted abrasive material into the pipe line in the reverse direction untilthe adherent material and its absorbed moisture have been removed and a substantial portion of fresh dry material has adhered to the moist deposits and substantially prevents the further passage of the gas current through the pipe line, and continuing such reversals until the deposits are sufficiently dried and abraded by the abrasive material.

GUSTAF MALMRO'S. 

